The present invention relates to a measuring device such as a micrometer, slide calipers, a depth gauge or a height gauge and contemplates to automatically establish a constant measuring pressure independently of the intention of a measurer.
A measuring device such as a micrometer, slide calipers, a depth gauge or a height gauge is used to measure the length of a test piece (an object to be measured) by having its movable portion contacting with the test piece. The measurement of the length of a test piece by the measuring device of that type is performed by manually moving the movable portion until its portion contacts with the test piece and by clamping the test piece together with a stationary portion.
As a result, the measuring device has an advantage that the operation can be performed easily and promptly. However, since the test piece has to be held by the force of the fingers of the measurer, the indicated values have a tendency to become different in accordance with the changeable measurers and with the shapes of the test pieces so that the measurements cannot be always performed accurately.
In view of this tendency, there has been conceived a device, in which a spring is interposed between the movable portion and a lift knob where the finger of the measurer is applied to move the movable portion so that the measuring pressure for holding the test piece may be made constant by the elastic force of the spring. The device of this type also has a tendency that the spring is warped, when the lift knob is pushed by a stronger force than a usual one, thereby to invite similar results to the aforementioned ones.